Courtesy Clemson University
If, when you were young, your parents told you listening to music like The Beatles would rot your brain, they could have been metaphorically correct if you were a tree. This is a lesson learned often on the farm and one brought home this summer at the Griffith Park Observatory in Los Angeles, where a pine tree planted in memory of musician and gardener George Harrison in 2004 was killed by beetle damage.
Beetles are hungry, destructive insects. Some—like the bark beetles that likely took the life of Harrison’s tree memorial—have a taste for trees, no matter what the tree might mean to others. Others—like those *&S^% Colorado potato beetles—give me fits when they go after my potatoes on the farm.
Members of The Beetles
Pine trees are commonly attacked by bark beetles. There are more than 600 species of these in the U.S. California alone has 200 of them. Twenty of California’s are invasive, and 10 have shown up since 2002.
If you visited the George Harrison tribute tree, you probably wouldn’t have noticed the bark beetles doing any damage—they’re smaller than a grain of rice. (You can see some up-close and ugly images here, though.) If you are personally invested in a tree, like those on your farm, you can look really closely to see the damage the bark beetles can do. They burrow through the inner bark—the ploem-cambial region, for you tree nerds—and this starts a sap flow and leaves what looks like sawdust—called frass—in bark crevices and around the base of the tree. You might have seen small holes where the beetles entered the tree, too.
While the beetles are in there, the females lay their eggs under the outer bark. These eggs hatch into larvae that carve channels to their pupation locations, inside or beneath the bark. These develop into adults and go on to delight in—that is destroy—additional trees. Most California bark beetle species go through this cycle two or more times each year. That’s a lot of trees at risk on your farm.
Stop the Music
Healthy trees are least susceptible to beetle damage, as you might imagine. Once these insects arrive—much like The Beatles’ groupies—they’re hard to get rid of. There are a few things you can do:
- Plant native trees and trees adapted to your area—this will reduce tree stress and boost tree health.
- If you have a known beetle problem, plant trees not susceptible to that type of beetle.
- Prune and get rid of bark-beetle-infested limbs. Take out entire trees, if necessary, because you don’t want the larvae to develop and move on to other trees on the farm.
- Seal off firewood in small piles with thick, clear, UV-degradation-resistant plastic in a sunny spot to prevent beetles from moving in and to kill any that are hiding there.
- Bring in beetle enemies, such as woodpeckers and parasitic wasps.
- Enlist a forester or your cooperative-extension agent to keep beetles in check on your farm with pheromones.
If all of this fails, try playing some George Harrison tunes. A little bit of “What is Life” will have you lamenting what you already know: Farm trees need support, too.
Get more help preventing beetles and other pests:
- 14 Companion Plants to Repel Beetles and Other Garden Pests
- 2 Organic Ways to Control Harlequin Bugs
- 4 Ways to Prevent Japanese Beetles
- 13 Headache-Inducing Garden Pests and How to Control Them
- Pest Alert: Asparagus Beetles